Sienna Spiro is an English musician and composer known for her work in jazz-influenced vocal music and contemporary songwriting. Active from the 2010s onward, she has performed and recorded material that blends traditional jazz standards, cabaret sensibilities and modern pop-jazz arrangements, often emphasizing nuanced phrasing and intimate vocal delivery. Her repertoire and collaborations draw on classic jazz instrumentation and small ensemble settings, with an approach that highlights melodic clarity and lyrical storytelling. Based in the United Kingdom, her work sits within the broader contemporary British jazz and vocal performance scene.